Storage and transport cask for nuclear waste

ABSTRACT

A nuclear waste cask in one embodiment includes an axially elongated cask body defining a longitudinally-extending opening forming an entrance to an internal storage cavity of the cask configured for holding radioactive nuclear waste materials. A closure lid detachably coupled to the cask body at the top opening seals the cavity. A cask locking mechanism includes a plurality of first locking protrusions spaced apart on the lid which are selectively interlockable with a plurality of second locking protrusions spaced apart on the cask body to lock the lid to the cask body. The first locking protrusions may be disposed on slideable locking bars moveable between locked and unlocked positions while the lid remains stationary on the cask body. Hydraulic or pneumatic actuators may be used to change position of the locking bars. The cask and lid may include other features such as impact absorbers and lifting elements.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/831,809 filed Jun. 3, 2022, which is a continuation of U.S. patentapplication Ser. No. 17/181,439 filed Feb. 22, 2021, which claims thebenefit of U.S. Provisional Application No. 62/979,640 filed Feb. 21,2020; which are all incorporated herein by reference in theirentireties.

BACKGROUND

The present invention relates generally to systems and vessels fortransporting and storing high level radioactive nuclear waste materials,and more particularly to a box-type cask in one embodiment for transportand storage of radioactive nuclear waste materials.

The overpacks or casks used to store neutron activated metal and otherradiated non-fissile high level radioactive waste, such as thatresulting from operation nuclear power generation plants or other typefacilities, is typically an open-top cylindrical structure with a boltedcircular lid. Such a cask is inefficient to load all types of nuclearwaste materials not limited to spent nuclear fuel into the cask. Theradiation waste materials are often too large and/or may be irregularshaped for insertion through the narrow top access opening in suchcylindrical casks which leads to the internal storage cavity. Further,the act of tightening the bolts once the cylindrical cask is packed withnuclear waste materials is a time consuming which exposes the workers toradiation dosage in proportion to the time needed to complete thetedious installation of the closure bolts.

Accordingly, there remains a need for an improved nuclear waste storagecask that can accommodate a wide variety of waste materials, and whichcan further be closed and sealed in an expedient manner to reduceradiation exposure of operating personnel handling the cask.

BRIEF SUMMARY

The present application provides a nuclear waste storage systemcomprising a radiation-shielded nuclear waste storage cask whichovercomes the shortcomings of the foregoing cylindrical type storagecasks described above for storing a wide variety of different nuclearwaste materials. In one embodiment, a longitudinally elongated box-typecask is disclosed comprising an essentially rectangular body withrectilinear cross sectional internal storage cavity configured forholding nuclear waste material, and a matching rectangular closure lid.The elongated large top opening leading into the storage cavity extendsfor a majority of the longitudinal length of the cask. In contrast tothe small circular opening at the top of cylindrical casks, the presentrectangular opening allows large and irregular shaped radioactive metalpieces of waste material to be loaded inside the cask storage cavity inan efficient and expedient manner without undue handling by operatingpersonnel, thereby reducing potential radiation dosage.

In one embodiment, the closure lid be coupled and sealed to the caskbody to close the top opening through a quick connect-disconnect jointthat does not utilize any threaded fasteners. Instead, a slider lockingmechanism comprising mechanically interlocking protrusions provided onperipheral portions of each of the lid and correspondingly cask bodyaround the cask top opening is employed. While the lid remainsstationary on the cask body, the locking protrusions on the lid areslideably relative to the locking protrusions on the cask body betweenlocked and unlocked positions or states. The locking protrusions may bearrayed and spaced apart perimetrically around the lid and cask body.The locking protrusions may be wedge-shaped in one embodiment to producea wedging-action when mutually engaged which effectively locks the lidto the cask body and seals the nuclear waste contents inside the cask. Agasket at the lid to cask body interface is compressed by thewedging-action to form a gas-tight seal of the cask storage cavity whichcompletes the containment barrier. There is no exchange of air betweenthe ambient environment and the storage cavity in one embodiment.

The term “nuclear waste material” as used herein shall be broadlyconstrued to mean any type or form of radioactive waste material whichhas been irradiated by a source of radiation. Such irradiation may occurin a nuclear power generation plant with nuclear reactor, or other typesof facilities. As one non-limiting example, the radioactive nuclearwaste materials may be associated with decommissioning orrepair/maintenance of a nuclear facility, and may therefore include awide variety of sizes and shapes of pieces of equipment (including partsof the reactor), structural components/members, parts, debris, scrap, orsimilar which have been irradiated and generate radiation.

In one aspect, a cask for containing radioactive materials comprises: acask body comprising an opening forming a passageway into an internalstorage cavity of the cask; a closure lid configured to be detachablycoupled to the cask body to enclose the opening; and a locking mechanismcomprising at least one first locking member and at least one secondlocking member, the first and second locking members slideable relativeto one another to alter the locking mechanism between: (1) a first statein which the closure lid can be removed from the cask body; and (2) asecond state in which the first and second locking members engage oneanother to prevent the closure lid from being removed from the caskbody.

According to another aspect, a cask for containing radioactive materialscomprises: a longitudinal axis; an axially elongated cask body defininga top opening forming an entrance to an internal storage cavity ofnon-cylindrical cross-sectional configuration, the cavity configured forholding radioactive waste materials; and a closure lid detachablycoupled to the cask body at the top opening.

According to another aspect, a method for locking a radioactive wastestorage cask comprises: positioning a closure lid on a cask body over anopening leading into an internal storage cavity; inserting a peripheralarray of first locking protrusions on the lid between and through aperipheral array of second locking protrusions disposed on the cask bodyaround the opening; slideably moving the first locking protrusionsbeneath the second locking protrusions; and frictionally engaging thefirst locking protrusions with the second locking protrusions; whereinthe lid cannot be removed from the cask body.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein likeelements are labeled similarly and in which:

FIG. 1 is top perspective view of a polygonal cask configured forstorage of nuclear waste materials according to one embodiment of thepresent disclosure;

FIG. 2 is an enlarged detail taken from FIG. 1 ;

FIG. 3 is a bottom perspective view of the cask of FIG. 1 ;

FIG. 4 is an exploded top perspective view thereof showing the lidremoved;

FIG. 5 is an exploded bottom perspective view thereof;

FIG. 6 is a longitudinal side elevation view thereof;

FIG. 7 is a lateral end elevation view thereof;

FIG. 8 is a top plan view thereof;

FIG. 9 is a bottom plan view thereof;

FIG. 10 is a longitudinal transverse cross-sectional view thereof;

FIG. 11 is an enlarged detail taken from FIG. 10 ;

FIG. 12 is a top perspective view of the closure lid;

FIG. 13 is an enlarged top perspective view of an end portion of thelid;

FIG. 14 is a bottom perspective view of the lid;

FIG. 15A is a top exploded perspective view of the lid;

FIG. 15B is an enlarged detail taken from FIG. 15A;

FIG. 16 is a bottom exploded perspective view of the lid;

FIG. 17A is a partial longitudinal cross sectional view of the lidshowing the cask locking mechanism in a locked position or state;

FIG. 17B is a partial longitudinal cross sectional view of the lidshowing the cask locking mechanism in an unlocked position or state;

FIG. 18 is an enlarged detail in perspective view of a portion of thecask interior at the top opening showing the cask body lockingprotrusion arrangement;

FIG. 19 is an exploded perspective view of a portion of a longitudinalsidewall of the cask body showing a locking handle assembly in explodedview as well;

FIG. 20 is an enlarged perspective view of the locking handle assemblyin the inward blocking position locked with a cable-lock securitytag/seal in place;

FIG. 21 is a second enlarged perspective view of the locking handleassembly in the outward non-blocking position on the cask body;

FIG. 22 is an enlarged detail in perspective view of a portion of thecask interior at the top opening in a corner region showing the caskbody locking protrusion arrangement on adjoining walls of cask body;

FIG. 23 is a transverse cross sectional view of the cask body and lidshowing the lid removed;

FIG. 24 is an enlarged detail taken from FIG. 23 showing the lockinghandle assemblies on the longitudinal sidewalls of the cask body in theoutward non-blocking position;

FIG. 25 is a transverse cross sectional view of the cask body and lidshowing the lid in position on the cask body;

FIG. 26 is an enlarged detail taken from FIG. 25 showing the lockinghandle assemblies in the inward blocking position;

FIG. 27 is a perspective view of an actuator assembly for moving lockingbars of the lid;

FIG. 28 is a cross sectional view thereof;

FIG. 29 is a first schematic diagram of a sequential method for lockingthe cask of FIG. 1 ;

FIG. 30 is a second schematic diagram thereof;

FIG. 31 is a third schematic diagram thereof; and

FIG. 32 is a fourth schematic diagram thereof.

All drawings are schematic and not necessarily to scale. Features shownnumbered in certain figures which may appear un-numbered in otherfigures are the same features unless noted otherwise herein. A generalreference herein to a figure by a whole number which includes relatedfigures sharing the same whole number but with different alphabeticalsuffixes shall be construed as a reference to all of those figuresunless expressly noted otherwise.

DETAILED DESCRIPTION

The features and benefits of the invention are illustrated and describedherein by reference to non-limiting exemplary (“example”) embodiments.This description of exemplary embodiments is intended to be read inconnection with the accompanying drawings, which are to be consideredpart of the entire written description. Accordingly, the disclosureexpressly should not be limited to such exemplary embodimentsillustrating some possible non-limiting combination of features that mayexist alone or in other combinations of features.

In the description of embodiments disclosed herein, any reference todirection or orientation is merely intended for convenience ofdescription and is not intended in any way to limit the scope of thepresent invention. Relative terms such as “lower,” “upper,”“horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and“bottom” as well as derivatives thereof (e.g., “horizontally,”“downwardly,” “upwardly,” etc.) should be construed to refer to theorientation as then described or as shown in the drawing underdiscussion. These relative terms are for convenience of description onlyand do not require that the apparatus be constructed or operated in aparticular orientation. Terms such as “attached,” “affixed,”“connected,” “coupled,” “interconnected,” and similar refer to arelationship wherein structures are secured or attached to one anothereither directly or indirectly through intervening structures, as well asboth movable or rigid attachments or relationships, unless expresslydescribed otherwise.

As used throughout, any ranges disclosed herein are used as shorthandfor describing each and every value that is within the range. Any valuewithin the range can be selected as the terminus of the range. Inaddition, any references cited herein are hereby incorporated byreference in their entireties. In the event of a conflict in adefinition in the present disclosure and that of a cited reference, thepresent disclosure controls.

The terms “seal weld or welding” as may be used herein shall beconstrued according to its conventional meaning in the art to be acontinuous weld which forms a gas-tight hermetically sealed jointbetween the parts joined by the weld. The term “sealed” as may be usedherein shall be construed to mean a gas-tight hermetic seal.

FIGS. 1-28 show various aspects of the nuclear waste transport andstorage system. The system includes nuclear waste transfer and storagecask 100 (hereafter nuclear waste cask for brevity) which is usabletransport and/or store high level nuclear waste materials. Cask 100comprises an elongated rectilinear-shaped cask body 101 defining alongitudinal axis LA and the lower part of the containment barrier forthe nuclear waste. The body 101 may have a rectangular cuboidconfiguration in one embodiment (as shown) comprising an axiallyelongated bottom wall 102, a parallel pair of longitudinal sidewalls 103attached to the bottom wall, and a pair of lateral end walls 104attached to opposite ends of the bottom wall between the sidewalls. Thelongitudinal sidewalls are attached to the longitudinal sides or edgesof the bottom wall. End walls 104 are oriented transversely andperpendicularly to longitudinal axis LA and longitudinal sidewalls 103,and the longitudinal sidewalls are oriented parallel to the axis to formthe box-like structure shown. In one embodiment, the sidewalls and endwalls may be welded to each other and in turn to the bottom wall to forma weldment. Four corners 107 are formed at the intersection of thesidewalls 103 and end walls 104 which extend vertically along the heightof the cask body 101.

Bottom wall 102 has a flat top surface 102 a and parallel opposing flatbottom surface 102 b. The bottom wall is configured to be seated on ahorizontal support surface such as a concrete pad. The interior andexterior surfaces of each of the longitudinal sidewalls 103 and endwalls 104 may be generally flat and parallel to each other as well.

Cask 100 may be used in horizontal position as shown when transportingand storing nuclear waste. In this case, the vertical direction isdefined for convenience of reference as being transverse andperpendicular to the longitudinal axis LA. A lateral direction isdefined for convenience of reference in the horizontal direction asbeing transverse and perpendicular to the longitudinal axis.

The bottom wall 102, longitudinal sidewalls 103, and end walls 104collectively define an internal storage cavity 105 configured forstoring nuclear waste materials previously described herein. The bottomwall, longitudinal sidewalls, and end walls define and circumscribe anaxially elongated top opening 106 forming an entrance to the cavity forloading nuclear waste materials therein. The longitudinally-extendingtop opening 106 extends for a substantial majority of the entire lengthof the cask body (less the thicknesses of the sidewalls and end walls).This provides a large opening which facilitates loading many differentshapes and sizes nuclear waste materials into the cask 100.

Longitudinal sidewalls 103 and lateral end walls 104 of the cask mayeach have a composite construction comprising a metallic innercontainment plate 110 adjacent to the storage cavity 105 and a metallicouter radiation dose blocker plate 111 abutted thereto. Bottom wall 102may similarly have a composite construction comprising a metallic innercontainment plate 112 adjacent to the storage cavity and a metallicouter radiation dose blocker plate 113. In some embodiments, as shown,an intermediate dose blocker plate 114 may be sandwiched between theinner containment plate and outer dose blocker plate when needed toprovide additional radiation shielding. In some non-limitingembodiments, the containment plates may be formed of steel alloy and theradiation dose blocker plates may be formed of a different steelmaterial such as for example stainless steel for protection againstcorrosion by the exterior ambient environment. A suitable thickness ofthe containment and blocker plates may be used as needed to effectivelyreduce the radiation emitted from the cask to within regulatorycompliant exterior levels for containment casks. As noted, the bottomwall and walls of cask 100 may have an all metal construction withoutuse of concrete. However, in other possible embodiments, concrete andadditional or other radiation shielding materials includingboron-containing materials for neutron attenuation and variouscombinations thereof may be provided if additional radiation blocking isneeded. The bottom wall and wall construction materials used thereforedo not limit the invention.

With continuing reference to FIGS. 1-28 , cask 100 further includes alongitudinally elongated closure lid 200 which forms the uppercontainment barrier. Lid 200 may be of rectangular shape in oneembodiment to match the rectangular cuboid configuration of the caskbody 101 shown. Lid 200 has a length and width sufficient to form acomplete closure of the top opening of the cask in order to fullyenclose and seal the internal storage cavity 105 of the cask and nuclearwaste materials. Lid 200 includes an outward facing top surface 201 andparallel bottom surface 202 facing cavity 105 of the cask body 101 whenpositioned thereon, parallel longitudinal sides 203 (i.e., long sides ofthe lid), parallel lateral ends 204 (i.e., short sides of the lid)extending between the longitudinal sides, and corners 205 (four asshown) at the intersection of the longitudinal sides and lateral ends.Top and bottom surfaces 201, 202 are the major surfaces of the lidhaving a greater surface area than other surfaces on the lid.

Referring additionally to FIGS. 10-17B, closure lid 200 may have acomposite construction comprising a metallic inner containment plate 206at bottom located adjacent to the storage cavity 105 when the lid isposition on the cask body 101, and a top metallic outer radiation doseblocker plate 207. Containment plate 206 defines bottom surface 202 ofthe lid and blocker plate 207 defines top surface 201. An insulationboard 208 may be sandwiched between plates 206 and 207 for protectionagainst fire event.

In one embodiment, a peripheral lid spacer frame 209 may be attached tothe bottom containment plate 206 of lid 200. Frame 209 has an openspace-frame structure which extends perimetrically around the bottomsurface 202 of the lid. The frame 209 may include an X-brace 209 aextending through the interior space defined by the peripheral linearmembers of the frame to add structural reinforcement and bracing. Whenlid 200 is positioned on cask body 101, inner containment plate 206 andframe 209 are received completely into storage cavity 105 of the cask(see, e.g., FIGS. 10 and 11 ).

A compressible gasket 220 may be disposed on the bottom surface 202 ofthe lid 200 to form a gas-tight seal at the interface between the lidand cask body. Gasket 220 has a continuous perimetrically extendingshape which is complementary configured dimensionally to conform to andcircumscribed the top end of the cask body 101 on all sides. Gasket 220therefore extends perimetrically along the tops of the longitudinalsidewalls 103 and lateral end walls 104 of the cask to form an effectiveseal. Gasket 220 may be formed of any suitable compressible material,such as elastomeric materials in some embodiments.

According to one aspect of the disclosure, a bolt-free cask lockingmechanism provided to lock and seal lid 200 to cask body 101. FIGS.10-18 and 22-28 in particular show various aspects of the bolt-free casklocking mechanism, which will now be further described in detail.

Lid 200 and cask body 101 include a plurality of locking features whichcooperate to form the locking mechanism. The cask locking mechanism maycomprise a plurality of first locking protrusions 212 spaced apart onthe lid which are selectively and mechanically interlockable with aplurality of second locking protrusions 214 spaced apart on the caskbody to lock the lid to the cask body. First locking protrusions 212 aremovable relative to the lid and cask body 101, whereas second lockingprotrusions 214 are fixed in position on and stationary with respect tothe cask body.

The locking features of the lid 200 comprises at least one first lockingmember 212 a, which may be in the form of a linearly elongated lockingbar 210 for locking the lid to the cask body (see, e.g., FIGS. 15B and29-32 ). In one embodiment, a plurality of elongated locking bars 210are arranged perimetrically around the outer peripheral portions of thelid on longitudinal sides 203 and lateral ends 204. First lockingprotrusions 212 are formed on and may be an integral unitary structuralpart of the locking bars in one embodiment being formed of singlemonolithic piece of cast or forged metal. In other possible lesspreferred but satisfactory embodiments, locking protrusions 212 may bediscrete elements separately attached to the locking bars 210 viamechanical fasteners or welding.

Locking bars 210 are slideably disposed in corresponding outward facingelongated linear guide channels 211 formed in the longitudinal sides andlateral ends of the lid 200. The locking bars are movable back and forthin opposing directions within the guide channels relative to the lid.Each locking bar 210 includes a plurality of the first lockingprotrusions 212 which project outwardly from the bar beyond the outwardfacing surfaces of the longitudinal sides 203 and lateral ends 204 ofthe lid. The linear array of locking protrusions 212 are spaced apart toform openings 213 between adjacent locking protrusions for passing thesecond locking protrusions 214 on the cask body 101 therethrough, asfurther described herein.

The longitudinal sides 203 and lateral ends 204 of the lid 200 may eachinclude at least one locking bar 210. In one preferred but non-limitingembodiment, as illustrated, the lateral ends 204 of the lid may includea pair of the locking bars 210 and the longitudinal sides 203 of the lidmay similarly include a pair of locking bars. This forms a uniquearrangement and interaction between the locking bars to maintain alocked position, as further described herein.

The corresponding locking features of the bolt-free cask lockingmechanism on cask body 101 include at least one second locking member214 a comprising the second locking protrusions 214. Locking member 214a may comprise upper portions of cask body 101 in which the secondlocking protrusions 214 and related features such as locking slot 216described below are integrally formed with the cask body inside storagecavity 105. Locking protrusions 214 are fixedly disposed in lineararrays on the cask body adjacent to top ends of the longitudinalsidewalls 103 and lateral end walls 104 of the body and cask body topopening 106. The second locking protrusions 214 are therefore stationaryand not movable relative to the cask body. The second lockingprotrusions 214 project inwardly into the nuclear waste storage cavity105 from the interior surfaces of the longitudinal sidewalls 103 andlateral end walls 104 of the cask body. Second locking protrusions 214therefore are arranged around the entire perimeter of the cask body tointerface with the first locking protrusions 212 of lid 200.

The linear array of second locking protrusions 214 are spaced apart toform openings 215 between adjacent locking protrusions for passing thefirst locking protrusions 212 on the lid therethrough. A linearlyelongated locking slot 216 is formed and recessed into the cask body 101immediately below the second locking protrusions 214 on each of thelongitudinal sidewalls 103 and end walls 104 of the cask body. Thelocking slots 216 form continuous and uninterrupted inwardly openstructures having a length which extends beneath at least all of thesecond locking protrusions on each of the longitudinal sidewalls 103 andlateral end walls 104 of the cask body as shown. Locking slots 216therefore extend for a majority of the lengths/widths of the cask bodylongitudinal sidewalls and end walls. Locking slots 216 are incommunication with the openings 215 between the second lockingprotrusions 214 to form an insertion pathway for the first lockingprotrusions 212 of lid 200 to enter the locking slots.

In one preferred but non-limiting construction, the openings 215 betweenthe second locking protrusions 214 and the elongated locking slots 216may be formed as recesses machined into the cask body 101 by removingmaterial from longitudinal sidewalls 103 and lateral end walls 104. Thematerial remaining therefore leaves the second locking protrusions 214in relief. Second locking protrusions 214 therefore in this case areformed as integral unitary and monolithic parts of the cask bodymaterial. In other possible constructions, however, the second lockingprotrusions 214 may be separate structures which are welded or otherwisefixedly attached to the cask body 101. In this latter possibleconstruction, no locking slot 216 is formed but the cask lockingmechanism may nonetheless still function satisfactorily to lock the lidto the cask body. In yet other possible constructions, the secondlocking protrusions 214 and locking slots 216 may be formed on linearlyelongated closure bars of metal having the same composite constructionas the longitudinal sidewalls 103 and end walls 104 previously describedherein. The closure bars are in turn welded onto the tops of eachlongitudinal sidewalls and end walls to produce the same structure inthe end as illustrated herein.

With continuing reference to FIGS. 10-18 and 22-28 , the first andsecond locking protrusions 212, 214 may be generally block-shapedstructures having a rectangular configuration. In one preferred butnon-limiting embodiment, the first and second locking protrusions mayeach be wedge-shaped defining locking wedges having at least one taperedlocking surface 217 or 218. The locking protrusions may be configuredand arranged such that the tapered locking surfaces 217 of the firstlocking protrusions 212 on lid 200 are each slideably engageable withone of the tapered locking surfaces 218 of a corresponding secondlocking protrusion 214 of the cask body 101. In one embodiment, thetapered locking surfaces 217 of the first locking protrusions 212 on lid200 may be formed on a top surface thereof, and the tapered lockingsurfaces 218 of the second locking protrusions 214 on cask body 101 maybe formed on a bottom surface thereof. When the first and second lockingprotrusions are engaged to lock the lid to the cask body, the taperedlocking surfaces 217, 218 become slideably engaged forming a generallyflat-to-flat interface therebetween. This creates a wedging-action whichdraws the lid 200 towards against the cask body 101 to fully compressthe gasket 220 therebetween which forms a gas-tight seal of the caskinternal storage cavity 105 and its nuclear waste material content.

The tapered locking surfaces 217 and 218 preferably have the same taperangle A1 (see, e.g., FIG. 29 ) to form the generally flat-to-flatinterface therebetween when mutually and frictionally engaged via thewedging action. Any suitable taper angle A1 may be used. In onerepresentative but non-limiting examples, the taper angle A1 preferablymay be between about 2 and 20 degrees. Other tapered angles may be usedwhere appropriate.

The locking bars 210 with first locking protrusions 212 on lid 200thereon are slideably movable between a locked position or state (see,e.g. FIG. 17A) in which the first and second protrusions 212, 214 aremutually engaged to prevent removal of the lid 200 from the cask body101 (see, e.g. FIG. 11 ), and an unlocked position or state (see, e.g.FIG. 17B) in which the first and second protrusions are disengaged toallow removal of the lid from the cask body in a vertical directiontransverse to longitudinal axis LA of the cask.

To move the locking bars 210 with sufficient applied force tofrictionally interlock the first and second locking protrusions 212,214, and to concomitantly minimize radiation dosage to operatingpersonnel, a remote lid operating system may be provided. This system isoperably coupled to each of the locking bars 210 and configured toadvantageously move the locking bars 210 between the locked and unlockedpositons from a remote radiation safe distance and area. This obviatesthe need for operators to manually operate the locking bars directly atthe cask during the lid-to-cask body closure and locking process.

In one embodiment, the remotely-operated lid operating system comprisesa local actuator 240 mounted on the top surface 201 of lid 200 for andcoupled to each of the locking bars 210. FIGS. 27 and 28 show actuators240 in isolation and detail. Each actuator 240 is an assembly which maygenerally comprise a cylinder-piston assembly 241 including cylinder 245and an extendible/retractable piston rod 242 slideably received insidethe cylinder. The cylinder-piston assembly is fixedly attached to lid200. Cylinder 245 may be fixedly mounted to the lid via a bolt 249passing through a tubular proximal mounting end 242 b as shown. Pistolrod 242 has a tubular distal working end 242 a fixedly coupled to thelocking bar 210 through an elongated operating slot 243 formed throughthe lid. The piston rod 242 is therefore moves the locking bar 210 inthe manner described herein. In one embodiment, slot 243 may be formedin a lid insert plate 243 a which in turn is mounted to the lid. Athreaded bolt 249 may be used to couple the piston rod to the lockingbar 210 via an intermediate block assembly comprising an upper mountingblock 246 and lower mounting block 247. Upper block 246 may be formed asintegral part of lid insert plate 243 a in some embodiments. Piston rod242 is fixedly bolted to upper mounting block 246. Upper mounting block246 is fixedly mounted to lower mounting block 247 via a plurality ofthreaded fasteners 248 which extend through the upper mounting block andare threadably engaged with the locking bar 210 (see, e.g., FIG. 28 ).The mounting block assembly provides a robust coupling of the pistonrods 242 to the locking bars 210 which can withstand the shear forcesgenerated when the cylinder-piston assemblies 241 are actuated to drivethe locking protrusions 212, 214 of the lid 200 and cask body 101 intolocking engagement.

The cylinder-piston assembly 241 may be either (1) hydraulicallyoperated wherein the working fluid is oil, or (2) pneumatically operatedwherein the working fluid is compressed air. Oil or air hoses arefluidly coupled to the cylinder-piston assemblies (not shown) andoperated from a remote hydraulic or pneumatic control unit in aconventional manner which comprises an air compressor or hydraulic pumpwith appropriate valving depending on the type of system provided. Whenactuated, the locking bar actuators 240 function to slide the lockingbars 210 between the locked and unlocked positions (FIGS. 17A and 17B)via extending or retracting the piston rod 242. It bears noting that theuse of hydraulic or pneumatic means to move the locking bars 210 appliesa greater force to the locking bars to form tight locking engagement viathe wedging-action between the first and second locking protrusions ofthe lid and cask body than could be provided by manually actuating thelocking bars 210. This advantage, coupled with avoiding exposure ofoperating personnel or workers to radiation dosage are notable benefitsof the present remote lid operating system.

Interaction between the locking protrusions 212, 214 and a relatedprocess/method for locking the nuclear waste cask 100 (i.e., lid 200 tocask body 101) are described farther below. The movement and functioningof the locking bars 210, however, is first further described.

FIGS. 17A and 17B show the locked and unlocked positions of the lockingbars 210 on lid 200. Retention features are provided as a safetymechanism which lock and retain the locking bars in the locked positionto prevent the lid 200 from being unintentionally unlocked from the caskbody 101, such as could potentially result from substantial forceimpacts occurring during transporting and handling the cask (e.g.,lifting, lowering, or loading the cask onto a transport vehicle/vessel),or during a regulatory postulated cask drop event.

In one embodiment, the locking bars 210 on the longitudinal sides 203 oflid 200 are moveable towards each other to form the unlocked positionshown, and away from each other to form the locked position shown.Conversely, the locking bars 210 on the lateral ends 204 of the lid aremoveable towards each other to form the locked position, and away fromeach other to form the unlocked position. This apparent dichotomy servesa purpose. When locking bars 210 on the lateral ends 204 of the lid aretherefore positioned and abutted together in the locked position,terminal end portions 210 a of the locking bars on the longitudinalsides 203 of the lid are positioned to overlap and engage/block thelocking bars on the lateral ends 204 of the lid from being moved apartto the unlocked position (see, e.g., FIG. 17A). This forms a firstlocking bar retention feature which locks the lid lateral end lockingbars 210 in the locked position.

The second locking bar retention feature acts on the locking bars 210 onthe longitudinal sides 203 of the lid 200 to lock the lid longitudinalside locking bars in the locked position. This retention featurecomprises a locking handle assembly 230 slideably mounted on each of thelongitudinal sidewalls 103 of the cask body 101 (see, e.g., FIGS. 17A-B,19-21, and 23-26). Each locking handle assembly 230 includes anelongated proximal handle 231 configured for receiving an applied forcegenerated by a user such as via grasping or a tool, a distal elongatedlocking block 233, and a securement bar 235. The locking block 233 iscoupled to the handle 231 by one or more elongated coupling rods 232 ofany suitable polygonal or non-polygonal cross-sectional shape.Preferably a pair of coupling rods 232 are provided. Securement bar 235is fixedly attached to the exterior surface of the cask bodylongitudinal sidewalls 103 (e.g., welded) and has a proximal end 235 awhich is insertable through an aperture 236 in the handle 231. End 235 amay project through aperture 236 when the handle assembly is fullyinward and can be secured in place (e.g., FIG. 20 further describedherein).

The locking handle assemblies 230 are positioned on each longitudinalsidewall 103 of the cask body 101 to allow the locking block 233 to bemanually and selectively moved into and out of the locking slots 216 onthe cask body sidewalls. A windows 234 formed in each longitudinalsidewall 103 allows the locking block 233 to access the guide channels216. More particularly, window 234 is formed in and extends completelythrough inner containment plate 110 of the longitudinal sidewalls 103 ofthe cask body. Locking block 233 is completely retractable from lockingslot 216 into the containment plate 110 to allow insertion of firstlocking protrusions 212 on locking bars 210 into and slideably movedalong the locking slot 216 beneath second locking protrusions 214 of thecask body. The outer radiation dose blocker plate 111 comprises a pairof holes 237 to permit the two coupling rods 232 to be coupled tolocking block 233 located inside the blocker plate in window 234 of theinner containment plate 110 (see, e.g., FIG. 18 ). A pair of cylindricalmounting flange units 239 may be used to fixedly mount each lockinghandle assembly 230 to the dose blocker plate 111 on the longitudinalsidewalls 103 of cask body 101 (see, e.g., FIG. 20 ). Flange units 239may be bolted/screwed or welded to the outer blocker plate 111. Theflange units 239 further act as standoffs to limit the maximum inwardprojection of the locking block 233 into the locking slot 216 of thecask body. The coupling rods 232 are slideably inward/outward throughthe flange units to change position of the locking handle assemblies230.

The locking handle assemblies 230 are moveable via handles 231 between(1) an inward blocking position in which the locking blocks 233 projectinto the locking slots 216 of the cask body 101 beneath the secondlocking protrusions 214, and (2) an outward non-blocking position inwhich the locking blocks 233 are completely retracted from the lockingslots. The non-blocking position allows locking bars 210 with firstlocking protrusions 212 thereon to enter and slide back and forth in thelocking slots 216 between the locked and unlocked positions (bothpreviously described herein) when the lid 200 is positioned on cask body101. Once the locking bars are in the locked position, a gap G is formedbetween each pair of locking bars on the longitudinal sides 203 of thelid (see, e.g., FIGS. 12 and 17A). Moving the locking handle assemblies230 to the inward blocking position locates the locking blocks 233 inand fills the gaps G on each longitudinal sidewall 103 of the cask body(within guide channels 211 of lid 200). The locking bars 210 thereforecannot be drawn back together to their unlocked position, therebylocking the locking bars in the locked position due to interferencebetween the locking blocks 233 and locking bars. To move the lockingbars 210 on longitudinal sidewalls 103 to the unlocked position, thelocking blocks 233 are first withdrawn via handles 231 of the lockinghandle assemblies 230 to re-open gap G, thereby allowing thelongitudinal sidewall locking bars to slide together again to theunlocked position.

When each handle assembly 230 is in the inward blocking position, thesecurement end 235 a of securement bar 235 is projected throughapertures 236 in handles 231. Any suitable commercially-availablecable-lock security tag or seal tag 238 as shown may be coupled throughhole 235 b in securement bar 235 to lock the handle assemblies in theinward blocking position. Should the cask 100 be impacted or droppedduring handled, the lid 200 will remain locked to the cask body 101since the handle assemblies 230 cannot be moved outward to unlock thelid. The security tag also provides visual indication that the lid is inthe locked position to operating personnel. This is especially helpfulin situations where the cask lid 200 may be loaded with radioactivematerials and locked to the cask body 101 at one location, and then thecask is transported to a more remote receiving location. The crew at thereceiving location can readily confirm the lid is in the locked positionor state.

A process or method for locking the nuclear waste storage cask 100 usingthe foregoing features will now be briefly described. FIGS. 29-32 aresequential views showing the relationship between the first and secondlocking protrusions 212, 214 during the lid mounting and cask lockingprocess.

The process or method generally includes first placing the locking bars210 on longitudinal sidewalls 103 and lateral end walls 104 of lid 200in their unlocked position and the locking blocks 233 on locking handleassemblies 230 in their non-blocking positions which retracts thelocking blocks 233 from the locking slots 216 on the longitudinalsidewalls 103 of the cask body 101 (FIG. 17B). The locking bar actuators240 or manual means may be used to perform the foregoing step. Thelocking bars 210 on longitudinal sides 203 of lid 200 are together, andlocking bars on lateral ends 204 of the lid are spaced apart forming gapG therebetween as shown. The lid is positioned over and align with thecask body 101 wherein the lid first locking protrusions 212 arevertically aligned with the openings 215 between second lockingprotrusions 214 on the cask body (FIG. 29 ).

Next, the closure lid 200 is lowered and positioned on top of the caskbody 101 over the top opening 106. This step first vertically insertsthe peripheral array of first locking protrusions 212 on locking bars201 of lid 200 between the peripheral array of second lockingprotrusions 214 disposed on the cask body 101 around the top opening(FIG. 30 ). As the lid engages the top of the cask body 101, the firstlocking protrusions pass completely through the openings 215 between thesecond locking protrusions 214 and enter the horizontally elongatedlocking slots 216 in a position below the second locking protrusions(FIG. 31 ). In turn, the second locking protrusions 214 pass throughopenings 213 between the first locking protrusions 212 and becomepositioned above the first locking protrusions.

The process or method continues with then sliding the locking bars 210to their locked positions (FIGS. 17A and 31 ), which moves the firstlocking protrusions 212 beneath the second locking protrusions 214 in ahorizontal locking plane oriented parallel to the bottom wall 102 andpassing through the locking slots 216. This step may be performed byactuating the hydraulic or pneumatic cylinder-piston assembles 241 ofthe locking bar actuators 240 from a location remote from the cask tominimize radiation exposure of operating personnel. Sliding the lockingbars 210 slideably and frictionally engages the first lockingprotrusions 212 of the lid with bottom surfaces of the second lockingprotrusions 214 of the cask body 101. Specifically, the tapered lockingsurfaces 217, 218 of the wedge-shaped locking protrusions 212, 214become mutually locked in increasingly tightening frictional engagementvia the wedging-action produced. This draws lid 200 downward with addedforce beyond the weight of the lid alone onto and against the cask body101 to fully compress gasket 220 and seal the cask cavity 105. Thegasket is now compressed further than when the lid 200 first engages thecask body before the cask locking mechanism is actuated to draw the lidfarther downward.

Now that the lid 200 is fully coupled to the cask body 101, the lockinghandle assemblies 230 may be moved to their inward blocking positions toinsert the locking blocks 233 between each pair of locking bars 210 onthe longitudinal sides 103 of the lid, thereby preventing sliding andunlocking of the longitudinal side locking bars (FIG. 17A). The handleassemblies therefore retain the locked positions of the locking bars onthe cask longitudinal sidewalls 103, which in turn retains the lockingbars on the cask end walls in the locked position as previouslydescribed herein.

It bears noting that although the locking bars 210 with lockingprotrusions 212 are shown and described herein as being slideablymounted to the lid 200 and locking protrusions 214 are shown anddescribed as being fixedly mounted to the cask body 101 in oneembodiment, in other embodiment the arrangement may be reversed.Accordingly, the locking bars 210 may be slideably mounted to guidechannels 211 formed in the cask body while the fixed locking protrusions214 may instead be fixedly mounted to the closure lid. This alternatearrangement provides the same benefits and is operated in the samemanner previously described herein. The locking bar hydraulic orpneumatic actuators 240 in turn would be mounted to the cask body foroperating the locking bars 210.

Although the cask locking mechanism with locking bars 210 and lockingprotrusions 212, 214 are shown and described herein as being applied toa box-shaped rectangular cuboid cask body and rectangular lid, thelocking mechanism may be applied with equal benefit to a conventionalcylindrical cask body and circular lid. The fixed second lockingprotrusions 214 may be arranged on either the cylindrical cask body orlid, and the locking bars 210 may be mounted on the other one of thecask body or lid. The locking bars and guide channels for thecylindrical cask application may be arcuately curved and operated viathe hydraulic or pneumatic locking bar actuators 240 previouslydescribed herein if mounted on either the cask body or circular lid.Alternatively, both the locking protrusions 212, 214 may be fixedlymounted to the cylindrical cask body and lid, and the slideable lockingbars may be omitted. In this case, the lid may simply be rotatedrelative to the cylindrical cask body to slideably and frictionallyengage the wedge-shaped locking protrusions to form a breech lock typeclosure. The lid may be rotated via assistance form thehydraulic/pneumatic actuators. Based on the foregoing alternativeembodiments of the cask locking mechanism and description alreadyprovided herein, it is well within the ambit of those skilled in the artto implement any of these options without undue experimentation.

With general reference to FIGS. 1-10 and 21-23 , an impact absorptionsystem is provided to protect the cask 100 and containment barrier fromundue damage should the cask be forcibly impacted or dropped duringtransport and handling. In one embodiment, each of the longitudinalsidewalls 103 and lateral end walls 104 of the cask body 101 comprises aplurality of outwardly protruding impact absorber bars 140 fixedlycoupled thereto. The closure lid 200 and bottom surface 102 of the caskbody may also include multiple impact absorber bars 140 fixedly coupledthereto. The bars 140 may be each configured and arranged in appropriatelocations on and in a pattern appropriate to meet regulatoryrequirements (e.g., Nuclear Regulator Commission or NRC) for surviving apostulated cask impact/drop event. In one embodiment, the impactabsorber bars 140 may be configured as rectangular blocks of suitablethickness and dimension for the intended purpose. The locking handleassemblies 230 on longitudinal sidewalls 103 of cask body 101 may eachbe protected between at least a pair of absorber bars 140 locatedproximately to the assembly on each side. These protective impactabsorber bars have depth measured perpendicularly to the exteriorsurface of the cask body longitudinal sidewalls 103 such that the handleassemblies 230 do not protrude outwards beyond the bars. In oneembodiment, the impact absorber bars 140 may be bolted to the cask bodyand lid (see, e.g., FIGS. 23-26 ). This allows the bars to be readilyreplaced if damaged during a cask drop/impact event. In otherembodiments, the bars 140 maybe welded thereto.

Each corner 107 of the cask body 101 and corners 205 of lid 200 may beprotected by corner impact absorbers 141 fixedly coupled to cornerregions. Sets of upper and lower corner impact absorber are provided tocover and shield the lid and adjacent upper corner regions of the caskbody, and the bottom wall 102 and adjacent lower corner regions of thecask body, respectively. In one embodiment, the corner impact absorbers141 may be assemblies comprising an inner corner bracket 142 and outercorner blocks 143 fixedly coupled thereto. Inner corner brackets 142 maybe fixedly coupled to the cask body 101 at the lower corners of thebody, and the lid and/or cask body at the upper corners. In oneembodiment, the inner corner brackets 142 and corner blocks 143 may befixedly coupled to and movable with lid 200 as shown herein. The innercorner brackets 142 have inward facing concave recesses configured toconform to the perpendicular and squared off corners of the cask bodyand lid. The outer corner blocks 143 have concave recesses configured toconform to the exterior shape of the inner corner brackets 142. Theupper corner impact absorbers 141 extend vertically downwards from thelid over the upper corners of the cask body, and horizontally wraplongitudinally and laterally around the side regions of the corners onboth the cask body 101 and lid 200. The upper corner impact absorbersalso extend partially over the top of the lid at the corners. The lowercorner impact absorbers 141 horizontally wrap longitudinal and laterallyaround the side regions of the corners on the cask body 101 and bottomwall 102, and partially underneath the bottom wall. In one embodiment,the inner corner brackets 142 and outer corner blocks 143 may be boltedor screwed together via threaded fasteners. The inner corner brackets142 may in turn be bolted or screws to the cask body 101 and cask bodyand/or lid 200 via threaded fasteners as applicable.

To facilitate handling the cask 100, each of the longitudinal sidewalls103 of cask body 101 may include a plurality of outwardly protrudinglifting trunnions 150 fixedly attached thereto. Lifting trunnions 150may be generally cylindrical in configuration and of the retractabletype in one embodiment which are known in the art. The lid 200 in turnmay include a plurality of lifting lugs 151 for handling the lid. Lugs151 are fixedly attached to the lid. Lifting lugs may be generallycylindrical in configuration in one embodiment. Any suitable number oflifting trunnions and lugs may be provided as needed to safely lift andmaneuver the cask body and lid. Other configurations and constructionsof the lifting trunnions and lugs may be provided which are suitable forlifting and maneuvering the weight of cask body and lid in a stablemanner.

While the foregoing description and drawings represent some examplesystems, it will be understood that various additions, modifications,and substitutions may be made therein without departing from the spiritand scope and range of equivalents of the accompanying claims. Inparticular, it will be clear to those skilled in the art that thepresent invention may be embodied in other forms, structures,arrangements, proportions, sizes, and with other elements, materials,and components, without departing from the spirit or essentialcharacteristics thereof. In addition, numerous variations in themethods/processes described herein may be made. One skilled in the artwill further appreciate that the invention may be used with manymodifications of structure, arrangement, proportions, sizes, materials,and components and otherwise, used in the practice of the invention,which are particularly adapted to specific environments and operativerequirements without departing from the principles of the presentinvention. The presently disclosed embodiments are therefore to beconsidered in all respects as illustrative and not restrictive, thescope of the invention being defined by the appended claims andequivalents thereof, and not limited to the foregoing description orembodiments. Rather, the appended claims should be construed broadly, toinclude other variants and embodiments of the invention, which may bemade by those skilled in the art without departing from the scope andrange of equivalents of the invention.

1-50. (canceled)
 51. A method for locking a radioactive waste storage cask comprising: positioning a closure lid on a cask body over an opening leading into an internal storage cavity; inserting a peripheral array of first locking protrusions on the lid between and through a peripheral array of second locking protrusions disposed on the cask body around the opening; slideably moving the first locking protrusions beneath the second locking protrusions; and frictionally engaging the first locking protrusions with the second locking protrusions; wherein the lid cannot be removed from the cask body.
 52. The method according to claim 51, wherein when the first locking protrusions are arranged in spaced apart groups on a plurality of locking bars slideably mounted on the lid, the locking bars being slideably movable relative to the lid.
 53. The method according to claim 52, wherein the slideably moving step comprises sliding each of the locking bars from an unlocked position in which the first locking protrusions do not engage the second locking protrusions, to a locked position in which the first locking protrusions are positioned beneath the second locking protrusions.
 54. The method according to claim 51, wherein the frictionally engaging step comprises engaging a tapered locking surface on each of the first locking protrusions with a corresponding tapered locking surface on a respective one of the second locking protrusions which locks the lid to the cask body via a wedging action.
 55. The method according to claim 54, wherein engaging the tapered locking surfaces of the first and second locking protrusions draws the lid against the cask body in tightened engagement.
 56. The method according to claim 55, further comprising compressing a gasket between the lid and the cask body when the lid is drawn against the cask body.
 57. The method according to claim 53, wherein the slideably moving step comprises actuating a plurality of hydraulic or pneumatic actuators each coupled to a respective one of the plurality of locking bars which moves the locking bars between the unlocked and locked positions.
 58. The method according to claim 57, wherein the actuators are mounted on the lid.
 59. The method according to claim 58, wherein each actuator includes an extendible and retractable piston rod fixedly coupled to one of the locking bars.
 60. The method according to claim 53, wherein the frictionally engaging step comprises engaging a tapered locking surface on each of the first locking protrusions with a corresponding tapered locking surface on a respective one of the second locking protrusions which locks the lid to the cask body via a wedging action.
 61. The method according to claim 60, wherein engaging the tapered locking surfaces of the first and second locking protrusions draws the lid against the cask body in tightened engagement.
 62. The method according to claim 55, further comprising compressing a gasket between the lid and the cask body when the lid is drawn against the cask body.
 63. The method according to claim 51, wherein the waste storage cask has a horizontally elongated rectangular cuboid configuration. 